Skellige Armor Set
Armorer from Kaer Trolde stronghold in Skelige can sell you a full set of the Undvik's armor. (You have to have the expansion installed). The armor is of the 16th level. The set comes with an armor for Roach.
Nilfgaardian Armor Set
Another full set is based on the Nilfgaardian style. It can be bought in the Crow's Perch in Velen from the quartermaster. He stands to the left from the gate leading to the garrison (opposite to the Magnus's stand). The armor is of the 10th level. The set comes with an armor for Roach.
Elite Crossbow Set
Elite Crossbow Set consists of three kinds of this weapon and can be bought from various merchants. In Novigrad it can be bought from: a Merchant (1) [atlas map M6] Elven crossbow (level 21), a Blacksmith in Kaer Trolde castle in Skellige you can buy a Skellige Crossbow (level 14) and a quartermaster in Baron's Garrison offers Nilfgaardian Crossbow (level 7).